Polyphenol compounds and their use in lubricants and coatings

Abstract

A polyphenol compound wherein the aromatic rings are linked by direct bonds or by a divalent link in the ortho position relative to the --OH group and the end aromatic rings contain either oximino substituents or substituted alkylaminomethyl substituents in the ortho position. The compound can be coated onto a metal surface to give improved corrosion resistance. The metal surface can be zinc-coated steel or zinc phosphated steel. The polyphenol compound can be the only coating material or can be incorporated into a surface coating composition such as a paint.

We claim: 
     
       1. A compound of the general formula (I) ##STR15## wherein R is a substituted or unsubstituted hydrocarbon group containing from 6 to 30 carbon atoms; Y 1  is a group ##STR16##  or a group ##STR17## Y 2  is a group ##STR18##  when Y 1  is a group ##STR19##  or a group ##STR20##  when Y 1  is a group ##STR21## R 1  and R 2  are each independently hydrogen or a substituted or unsubstituted hydrocarbon group containing up to 20 carbon atoms;   R 3  and R 5  which may be the same or different are amino C 1-4  -alkyl, mercapto C 1-4  -alkyl or hydroxy C 1-4  -alkyl;   R 4  and R 6  which may be the same or different are hydrogen, hydrocarbon having up to 20 carbon atoms or as defined for R 3  and R 5  ;   X is a direct bond; and   n has a value of zero or does not exceed 10.   
     
     
       2. The compound of claim 1 having the general formula (II) ##STR22## wherein R, R 1 , R 2 , X and n are as defined. 
     
     
       3. The compound of claim 2 wherein R 1  and R 2  are both hydrogen. 
     
     
       4. The compound of claim 1 having the general formula IV ##STR23## wherein R, R 3 , R 4 , R 5 , R 6 , X and n are as defined. 
     
     
       5. The compound of claim 4 wherein R 3  and R 5  are C 1-4  alkyl. 
     
     
       6. The compound of claim 4 wherein R 4  and R 6  are hydroxy C 1-4  alkyl. 
     
     
       7. The compound of claim 1 wherein n is between 1 and 3. 
     
     
       8. The compound of claim 1 wherein R is a hydrocarbon group having at least 6 carbon atoms and not more than 24 carbon atoms. 
     
     
       9. A compound according to claim 2 wherein R is alkyl, X is a direct bond, and R 1  and R 2  are both hydrogen. 
     
     
       10. A composition which comprises a) a liquid solvent or dispersant or a surface coating composition; and   b) a compound as claimed in claim 1.   
     
     
       11. A composition according to claim 10 in which component (a) is a lubricating material and the composition is in contact with metal surfaces which are in relative motion.